Mattermost up to 10.11.13/11.5.1 Invite authorization

CVSS Meta Temp Score
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CTI Interest Score
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3.7$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Mattermost up to 10.11.13/11.5.1. This issue affects some unknown processing of the component Invite Handler. The manipulation leads to authorization. This vulnerability is referenced as CVE-2026-4273. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mattermost up to 10.11.13/11.5.1. It has been rated as problematic. This issue affects an unknown code of the component Invite Handler. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. Impacted is integrity. The summary by CVE is:

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate that the RefreshedToken differs from the original invite token during remote cluster invite confirmation which allows an authenticated attacker to bypass token rotation and reuse the original invite token via sending a crafted invite confirmation with a RefreshedToken matching the original token. Mattermost Advisory ID: MMSA-2026-00575

The weakness was published by daw10. The advisory is shared at mattermost.com. The identification of this vulnerability is CVE-2026-4273 since 03/16/2026. The exploitation is known to be difficult. The attack may be initiated remotely. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 316489 (Mattermost Server 10.11.x <= 10.11.13 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00570 / MMSA-2026-00575 / MMSA-2026-00582 / MMSA-2026-00622)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 10.11.14, 11.5.2 or 11.6.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (316489). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.7

VulDB Base Score: 3.1
VulDB Temp Score: 3.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 4.3
NVD Vector: 🔒

CNA Base Score: 3.7
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-863 / CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 316489
Nessus Name: Mattermost Server 10.11.x <= 10.11.13 / 11.5.x <= 11.5.1 Multiple Vulnerabilities (MMSA-2026-00570 / MMSA-2026-00575 / MMSA-2026-00582 / MMSA-2026-00622)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.14/11.5.2/11.6.0

Timelineinfo

03/16/2026 CVE reserved
05/18/2026 +62 days Advisory disclosed
05/18/2026 +0 days VulDB entry created
05/23/2026 +5 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: daw10
Status: Confirmed

CVE: CVE-2026-4273 (🔒)
GCVE (CVE): GCVE-0-2026-4273
GCVE (VulDB): GCVE-100-364445

Entryinfo

Created: 05/18/2026 10:01
Updated: 05/23/2026 14:48
Changes: 05/18/2026 10:01 (64), 05/23/2026 06:14 (11), 05/23/2026 14:48 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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